Huber P A, Redwood C S, Avent N D, Tanner M J, Marston S B
National Heart and Lung Institute, London, UK.
J Muscle Res Cell Motil. 1993 Aug;14(4):385-91. doi: 10.1007/BF00121289.
A partial clone of caldesmon, coding for the C-terminal 288 amino acids, was isolated from a human fetal liver cDNA library and sequenced. Expression of the clone in Escherichia coli produced a peptide called H1 (M(r) 32,549), which inhibited tropomyosin-enhanced actomyosin Mg(2+)-ATPase activity by 90% with half maximal inhibition at 0.03-0.04 mol H1 per mol actin. The inhibition could be reversed by Ca(2+)-calmodulin. H1 bound actin, Ca(2+)-calmodulin and tropomyosin and smooth muscle myosin with high affinities. This latter finding shows the presence of a second myosin-binding site in caldesmon. This was confirmed in thrombic digests of native sheep aorta and chicken gizzard caldesmon.
从人胎儿肝脏cDNA文库中分离出编码C末端288个氨基酸的钙调蛋白部分克隆并进行测序。该克隆在大肠杆菌中的表达产生了一种名为H1（相对分子质量32,549）的肽，它能抑制原肌球蛋白增强的肌动球蛋白Mg(2 +)-ATP酶活性达90%，在每摩尔肌动蛋白含0.03 - 0.04摩尔H1时达到半数最大抑制。这种抑制作用可被Ca(2 +)-钙调蛋白逆转。H1能与肌动蛋白、Ca(2 +)-钙调蛋白、原肌球蛋白和平滑肌肌球蛋白高亲和力结合。后一发现表明钙调蛋白中存在第二个肌球蛋白结合位点。这在天然绵羊主动脉和鸡砂囊钙调蛋白的凝血酶消化产物中得到了证实。
